An explosion during "extreme battery testing" Wednesday morning of a prototype energy cell at a General Motors battery research facility in Warren, Mich., injured one person and did major structural damage to the building.

At the heart of the explosion was a lithium-ion battery, according to a fire department official cited in local news reports. The morning blast did not, however, involve batteries that power the Chevrolet Volt, the new plug-in hybrid car whose batteries caught fire weeks after a crash test, General Motors said in a statement.

But the flap over the Volt battery fire has left some insiders feeling more than a little peeved and defensive at the amount of news media attention being devoted to what they say is an almost inevitable, if not routine, event in the business of battery research and extreme testing.

"The whole reason they have these labs is precisely to do this kind of aggressive testing – anticipating the worst thing a consumer could do with this product," says one expert with direct knowledge of the circumstances surrounding the explosion, who asked not to be named. "This is going to turn out to be a mountain out of a mole hill. Yeah, we're doing a lot of testing. That's what we have to do. Sometimes things explode."

“The incident is still under investigation by GM and the Warren authorities," the GM statement said. "Any information or discussion of the nature of the work in the lab or cause of the incident is entirely speculative and cannot be confirmed at this time. The incident was unrelated to the Chevrolet Volt or any other production vehicle. The incident was related to extreme testing on a prototype battery.”

"The debate over batteries recently really hasn't been about safety so much as about their longevity," says Tom Turrentine, director of the plug-in hybrid and electric vehicle research center at the University of California, Davis. "I think we are mostly over the hump with battery safety. But there's no question that battery labs are notorious for explosions when they're testing."

Lithium-ion batteries are attractive to automakers because they can hold so much power – about four times the amount of energy a conventional lead-acid battery. Even so, earlier lithium-ion batteries used in other commercial applications burst into flame on occasion. Laptop computer manufacturer Dell Computer recalled millions of batteries after a handful of its laptops burst into flames several years ago.

It's a peril automakers were well aware of. Automakers now building the Volt and other first generation plug-in vehicles that run primarily or exclusively on advanced lithium ion batteries have selected less-volatile battery chemistries – and added engineering safety features as well, industry experts say.

Robert Kruse, GM's then-executive director of global vehicle engineering for hybrids, electric vehicles, and batteries, explained his thoughts on emerging plug-in hybrid vehicle battery technology in a 2009 interview with the Monitor. On safety, cell chemistry, and to avoid "thermal runaway" in which lithium ion batteries have been known to burst into flames, "many layers of safety built into the Volt," Mr. Kruse said.

"We have adopted [independent] safety standards and have employed those requirements into our cell and pack designs. I can assure you we've met those standards with what we've designed."

Vehicle makers like GM are now on the hunt for new battery chemistries that hold a lot more energy than today's lithium ion battery, but are also less volatile. But it's a hunt fraught with occasional explosions.

"The challenge of the battery designer is to come up with a high voltage battery, but one that doesn't suffer from instability," says Donald Sadoway, professor of chemistry and an authority on new battery technology at the Massachusetts Institute of Technology. "If you have a high energy battery, that means you've got a lot of energy inside that case and you can, in an unabated release, end up with thermal events or, in an extreme case – an explosion."

Ann Marie Sastry isCEO of Sakti3, a next generation company that GM has invested in to produce a cutting-edge source of power for future vehicles that would far exceed conventional lithium ion batteries.

"Intensive testing is required right now to validate the technology for use by consumers," Dr. Sastry writes in an e-mail interview. "But, there are disruptive technologies coming down the pike which will obviate some of these challenges. So the today solution is to test, and the tomorrow solution is to productize the next generation technology, and that's why we are partnered with GM – they're taking the right approach."

Though not discounting the seriousness of any battery explosion, Dr. Sadoway says it's still much more dangerous to be near a gasoline explosion of equivalent energy value. Indeed, there were 184,000 vehicle fires in 2010 involving conventional gasoline-powered vehicles that killed 285 people and cost $1 billion in property damage, according to the National Fire Protection Association.

"If I had to choose," he says, "I would rather be present when a battery that explodes – rather than a car whose gas tank explodes."